There is a new $1/2 Morton 40, 50, or 80 lb Bags of System Saver II Pellets Printable coupon available over on Coupons.com. I found this one by leaving the zip code blank.
You can take this coupon over to Menards, where the 50 lb System Saver II Pellets are on sale for $5.49 with $1.50 Mail in Rebate (limit 4). Your net cost after rebate and coupon is just $3.49/bag! Note there is also a $1/2 coupon in the 3/25 RP or $1/3 in the 5/20 RP. The Menards sale and rebate runs through July 15th.